It's also something they do in Europe. Every public outdoor space has to be a brightly lit panopticon with no trees or shrubberies obstructing the view of anything as otherwise people could do crime, making law-abiding citizens feel unsafe.

Also, a large flat featureless lawn is considered much cheaper and easier to maintain than an actual garden or park where you would have to cut hedges, prune trees and you would have to drive your giant lawn mower tractor around stuff.